Did the Israelis use white phosphorus in populated areas?

The Israeli military is investigating whether its soldiers in the Gaza Strip improperly fired shells packed with white phosphorus, a powerful chemical munition that can cause serious and sometimes fatal burns.

It's the first time that Israel has acknowledged using the controversial weapon during the 22-day war in Gaza, although doctors, United Nations officials and independent human-rights groups have accused Israeli forces of firing phosphorus in civilian areas, a possible violation of U.N. conventions on warfare.

White phosphorus is legal under international law if it's used as a smoke screen to obscure troop movements or other military operations, but it's highly dangerous if it's deployed in heavily populated areas, because it can set skin on fire and burn all the way to the bone. Israel has said repeatedly that it used weapons consistent with international laws during its war against the militant Islamic group Hamas.

However, doctors interviewed Wednesday in Gaza said that so many patients had sustained burns consistent with white phosphorus that it appeared that Israeli forces used the chemical in highly populated areas.

At Shifa, the main hospital in Gaza City, doctors said that scores of patients had arrived with unusual burns, dark, foul-smelling splotches that grew deeper and blacker despite being washed with water and saline solution. The burns were so toxic in some patients that even those with relatively minor wounds, which ought to have been treatable, grew ill and died, the doctors said.

"We have never seen this type of injury or the number of such injuries," said Dr. Nafez Abu Shaaban, the head of the burns unit at Shifa. "These were not usual burns."

Patients told medics that they'd come into contact with smoking, spongelike wafers of phosphorus, and in some cases, doctors said, victims reached hospitals with wounds still smoking. White phosphorus burns as long as it's exposed to oxygen, and it can reach temperatures well over 1,000 degrees.

The injuries baffled Gaza's medical staff, adding to the enormous strain that the war placed on a bare-bones health system. Gaza health officials say that more than 1,300 Palestinians were killed in the fighting, two-fifths of them children and women. Thirteen Israelis died, 10 of them soldiers.

"Patients were asking me, 'What's the complication?' " said the British-trained Abu Shaaban, one of the most senior burn surgeons in Gaza. "I didn't have the answer."

In a Spartan room in the reconstructive-surgery wing of Shifa, 41-year-old Sabha Abu Halimah, her left hand still covered with thick black lesions, described how a shell had struck a house Jan. 4 — shortly after Israel launched its ground invasion of Gaza — in which 16 members of her family had taken shelter in the northern town of Beit Lahiya.

Her 10-year-old son, Zayed, screamed, "Mom, Mom, fire!" He perished in the flames, along with her husband and three other children, including a 15-month-old girl. Her clothes ablaze, Sabha Abu Halimah rolled on the ground for several minutes until most of the flames were extinguished, but when relatives brought her to the hospital several hours later, her burns were still smoking, doctors said.

Capt. Elie Isaacson, an Israeli military spokesman, said that an investigative team would probe the force's use of phosphorus "due to the number of claims that have come in from the press and from other sources."

Amnesty International, an independent human-rights advocacy group, said that its researchers had found phosphorus wedges, sometimes still smoking, in residential areas of Gaza. The group said that the wedges had been packed into steel artillery shells and fired from the air, a tactic that — depending on the height from which they're fired and the wind conditions — can scatter them over an area larger than a football field.

U.N. officials said they suspected that phosphorus-loaded shells caused a fire at the main U.N. warehouse in Gaza last week. Reporters who visited the warehouse Wednesday said that food that had been destroyed in the fire — intended for humanitarian relief — was still smoldering.

Donatella Rovera, an Amnesty International researcher, charged that Israel had used the weapon in "a completely unlawful manner, in places it should never be used under any circumstances."

The doctors also accused Israel of using another controversial weapon, known as dense inert metal explosives. These are compact munitions packed with bits of tungsten that explode on contact, spraying the tungsten like molten metal vapor over a small area. Some researchers have found that vaporized tungsten can cause cancer in mice.

Experts say that DIMEs are designed to minimize collateral damage, but they cause horrific damage at the impact point. Erik Fosse, a Norwegian doctor who has more than two decades of experience in war zones, said he saw several patients at Shifa who had virtually no injuries to their upper bodies but had lost most of their lower bodies — often requiring both legs to be amputated — suggesting that DIMEs had struck them.

Isaacson, the military spokesman, said that he'd look into the charges but repeated the assertion that Israeli weapons were used in accordance with international laws.